Paint spray guns and bells are used in a variety of industries to project paint onto an object. The words “spray gun” and “bell” may be used interchangeably in the present patent specification and claims. In the automobile industry, a particular paint spray gun/bell may be used to spray a number of paint coats of different colours onto parts for automobiles. The paint spray gun/bell must be regularly cleaned to remove curing and dry paint on the atomizer end of the spray gun/bell, and prior to the use of paint of a new colour to remove remnants of the first paint. Paint spray guns/bells are cleaned by projecting solvents at high velocity at them while contained within a chamber apparatus. The high velocities are required to remove dried paint from the atomizer end of the gun/bell. The cleaning is effected in a separate vessel to prevent leakage of spent solvent.
Canadian Patent No. 2,238,019 teaches a method and apparatus for cleaning spray guns. The apparatus for cleaning spray guns has a closed vessel having an inlet, a drain and a port for receiving an atomizer of a spray gun. A spray impeller is rotatable mounted within the vessel and in fluid communication with the inlet. The spray impeller has offset cleaning nozzles for projecting a cleaning spray towards the spray gun and a rotational nozzle for projecting a rotational spray to effect rotation of the spray impeller. The port has a seal for sealing while receiving the spray gun and positioning the atomizer of the spray gun in the cleaning spray.
Although the patented apparatus is effective for cleaning spray gun atomizers, it has been noted that a significant amount of spent cleaning solvent remains on the atomizer after it has been cleaned and removed from the closed vessel. The remaining solvent can represent a source of contamination in the paint booth. It would be desirable to have a cleaning apparatus that removes residual cleaning solvent from the atomizer before it is released from the closed vessel of the cleaning apparatus.
In an assembly line situation paint is applied in a cyclical process as many vehicles or components pass down the assembly line. So too, the apparatus for cleaning spray gun atomizers functions in a cyclical process: receiving an atomizer, effecting the cleaning, releasing the atomizer, and recovery and preparing to receive the next atomizer. It would be desirable for the cleaning apparatus to more efficiently capture and drain spent cleaning solvent from the closed vessel so that the duration of the recovery and preparation step could be reduced.
Paint residues which have been cleaned from paint guns can become deposited on the walls of the closed vessel. Over time a build up of paint can form, which if left could hamper the operation of the cleaning apparatus. Periodically the apparatus for cleaning spray guns must, itself, be taken off-line and cleaned. Down time for cleaning the apparatus for cleaning spray guns can disrupt the production cycle of the paint booth and potentially an entire assembly line. It would be advantageous for the apparatus for cleaning spray guns to have a mechanism for preventing retention of residual paint on the walls of the closed vessel.
While the apparatus described in Canadian Patent No. 2,238,019 does clean most surfaces of a spray gun atomizer, it can fail to clean the centre atomizer alley of the atomizer. It would be advantageous to provide an improved apparatus for cleaning spray guns which is capable of cleaning the centre atomizer alley in addition to cleaning other surfaces of the spray gun/bell. A further advantage could be realized if the means for cleaning the centre atomizer alley could function independently of the other cleaning nozzles, to permit the selective targeting of particular surfaces to customize the cleaning to match the particular type and model of spray gun being used on a given assembly line.